Loud speaker



LOUD. SPEAKER Filed April 13, 1928 INVE OR H R\ REDR AT RNEY Patented Dec. 29, 1931 UNITED STATES r TENT oFncs mm crnnnrx, or rams, rnancn, assmnon 'ro socmrn mouse name unc- TRIQUE, OF PARIS, FRANCE, A JOINT-STOCK COMPANY OF FRANCE LOUD srnaxnn Application filed April 18, 1928, Serial I'm-289,654, and in France April 29, 1887.

The present invention relates to apparatus of the kind used for the roduction, transmission or reproduction of sound, more particularly, to loud-speaking telephones or microphones. Still, more particularly it concerns among these apparatus comprising a vibrating diaphragm of large surface known as diffusers.

The invention consists essentially of a m particular form of construction of apparatus equipped with marginally unsupported diaphragms whereby the fragility of the latter in handling, use and transportation is eliminated.

Apparatus equipped with large-sized diaphragms are known in the prior art in which the diaphragm presents a perfectly free ed e or border, while being supported, at t e point where it is acted upon, by the means adapted to cause it to vibrate. In apparatus of this type, the reproduction of sounds is particularly good because deformations due to the fixing or attaching means clam ing the edge of the diaphragm more or less rm- 1y against supportin annuli or frames are entirely absent in t e reproduction. The only serious drawback they involve is that they are very delicate and sensitive and therefore easily broken when handled or' shipped.

Now, the present invention provides apparatus of the said sort wherein the element of fragility is obviated without any attendant inconvenience looked at from the viewpoint of freedom of vibration of the marginal portions of the diaphragm.

This end is realized in the following manner: The diaphragm of the curved or cone type of a definite geometric form (cone, m pyramid, paraboloid, etc.) is unsupported and free around its edges; in other words, it is not connected in any way, either elastically or otherwise, with the frame of the apparatus. Indeed, the edge is merely made to bear upon a band or strip of plastic material, such as rubber, or soft felt, preferably, conveniently interposed betweenthe edge of the diaphragm and the bodyof the apparatus.

59 The invention will be more readily undertwo diaphragms are employed, the dialar material is conveniently held in position,

stoodby the aid of the following detailed description and reference to the accompan ing drawings showing, by way of examp e, various embodiments of the basic idea of the invention as applied to loudspeaker apparatus. a I

In the drawings, Figure 1 illustrates an approved form of the invention; and Fi re 2 illustrates a modification thereofinw ich phragms being arranged in a suitable housmg.

i According toFigure 1, an annulusA made from soft rubber, very soft felt, or any simifor example, inside a grooved metal iece B which is shaped in accordance with t e contour of the tympanum. The piece B is sup- .portedby means of arms C radially disposed,

about the/casing containing an actuating I!! meanssuch as the casing-D in Figure 2. The tympanumor diaphragmof conical form E or of. other form (pyramidal or the like) is furnished with connecting means between its apex and the vibratin motor or actuating 17! means, whereby it is hel in position.

Figure 2 illustrates a modified form of construction, according to which the band made from flexible or elastic material, A, is placed upon a bearing surface formed on: the openin of a box or case B serving as the body 0 the apparatus. Fixed upon said case B is also the motor case D by the aid of arms C. It will be noted that the band A may preferably present a certain inclination "8! with reference to the surface of the tympanum E so as to providea more favorable bearing, it being understood that such a slope could be provided also in the arrangement illustrated in Figure 1. The case .B may to moreover be provided upon the other side (not shown in the illustration) with a second opening and a second tympanum actuated by an extension of the rodlet F.

The contact between the periphery of the vibrating diaphragm and the bearing band may be interrupted or discontinuous either b means of breaks or gaps in the band or el se because of notches or gaps formed in the circumference of the diaphragm,

The invention, as will be understood, is capable of a great number of modifications in design and application, according to the particular nature of the tympanum, the shape, nature and mode of attachment of the latter, of the band or ring of flexible materiahthe disposition of the armature or support of the apparatus in relation with the motor and the peripheral band, etc.

Having thus described the nature of my invention, What I claim is:

1. An acoustic device comprising a casing,

an opening in said casing, a layer of plastic material adjacent the edge of said opening,

said layer of plastic material being arranged to have an active face inclined to the plane of the edge of said opening, a supporting member, a driving motor supported by said supporting member, and a large conical diaphragm supported solely by its operative connection with said driving motor and the contact of its peripheral edge with the inclined active face of said layer of plastic material.

, 2. An acoustic device comprising a box like casing, openings in opposite sides of said casing, a layer of plastic material se cured to the edge of each opening, each of said layers of plastic material being arranged to have an active face inclined to the plane of the side of said casing a pair of diaphragms positioned Within said casing with their peripheral edges engaging the inclined faces of said layers of plastic material, a link connecting the apices of said diaphragm, a driving motor supported from one side oi said casing, and a driving connection from said driving motor to one of said diaphragms whereby said diaphragms are supported solely by said driving connection and by their peripheral engagement with said layvers of plastic material.

HENRI CHIREIX. 

